I like all of the Pokemon games, but most of my favorites are from Kanto. Probably because I watched a lot of the show then. "Bye bye Butterfree" is one of my favorites, even if it was sad.
Ash is weird. First he tries to trade Butterfree for a Raticate, but changes his mind because it was the first Pokemon he caught, then he ends up releasing it. Ash releases all of his cool Pokemon and refuses to catch any of the legendaries he meets. Come on Ash!